Wheel series
The terms wheel series and wheel show are applied in the broadcast television industry to television series in which two or more regular programs are rotated in the same time slot. Sometimes the wheel series is given its own umbrella title and promoted as a single unit instead of promoting its separate components.
The most successful example of a wheel series on American television was the NBC Mystery Movie, which debuted in 1971 on NBC and ran for seven seasons. Three of the shows in the rotation, Columbo, McCloud, and McMillan & Wife, were among the most successful shows on American television in the 1970s. Other wheel series from that period include:
NBC TV
ABC TV
The wheel series is not used today on American prime time network television, and the term is now considered archaic. Attempts at reviving the format were made in 1989 with the Mystery Wheel of Adventure (a series of made-for-syndication TV movies including six installments of a new version of The Saint), and in the 1990s with a format that rotated new editions of Columbo and Kojak, without lasting success.
Some cable channels have developed their own wheel series structures to group together short-run series or documentaries into a package that runs in a standard timeslot each week or each weeknight; examples of umbrella rotations include the Animal Planet Heroes grouping on Animal Planet, the three different productions grouped together as The Critical Hour on Discovery Health Channel, and the "Sci-Fi Series" collections on the Sci Fi Channel (now Syfy).